CN117190550A

CN117190550A - Accumulator heat exchanger

Info

Publication number: CN117190550A
Application number: CN202310661871.7A
Authority: CN
Inventors: F·塔尔霍恩; B·博巴德; M·胡克; D·维里塞尔
Original assignee: Carrier Corp
Current assignee: Carrier Corp
Priority date: 2022-06-07
Filing date: 2023-06-06
Publication date: 2023-12-08
Also published as: US20230392839A1; EP4290159A1

Abstract

An accumulator heat exchanger for use within a refrigeration system, the accumulator heat exchanger comprising: an accumulator vessel having an interior volume for accumulating a refrigerant fluid, wherein the accumulator vessel has an axial extent and a radial extent; a first inlet conduit for gaseous refrigerant and a first outlet conduit for superheated gaseous refrigerant; a heat exchange coil disposed within the accumulator vessel so as to provide an axially extending outer gap between an inner surface of the accumulator vessel and a radially outer surface of the heat exchange coil, wherein the heat exchange coil surrounds an axially extending inner volume of the heat exchange coil; a second inlet conduit for subcooling the refrigerant fluid and a second outlet conduit for subcooling the refrigerant fluid, wherein the second inlet conduit and the second outlet conduit provide an inlet flow path and an outlet flow path for the heat exchange coil; and a baffle covering a cross section of the inner volume of the heat exchange coil without interrupting the outer gap.

Description

Accumulator heat exchanger

Technical Field

The present disclosure relates to an accumulator heat exchanger and a refrigeration system including the accumulator heat exchanger. The present disclosure also relates to a method of heat exchanging using an accumulator heat exchanger.

Background

An accumulator is used in a refrigeration system to collect liquid refrigerant and thus prevent liquid refrigerant from entering the compressor where it may cause damage. Heat exchangers are used in refrigeration systems to control the temperature of the refrigerant. Accumulator heat exchangers providing the function of combining an accumulator and a heat exchanger are known. The accumulator heat exchanger may reduce the temperature of the first refrigerant stream before it enters the evaporator to increase its cooling capacity and at the same time increase the temperature of the second refrigerant stream before it enters the compressor to facilitate the formation of gaseous refrigerant from liquid refrigerant. Thus, heat may be extracted from the first refrigerant stream to form a subcooled refrigerant for use in the first portion of the refrigeration system, and the heat may be usefully employed to heat the second refrigerant stream to form a superheated refrigerant for use in the second portion of the refrigeration system.

It is desirable to increase the heat exchange between the two refrigerant streams in order to further improve the cooling capacity of the refrigeration system and the overall efficiency of the refrigeration system.

It is known to use an additional heat exchanger, such as a liquid vapor heat exchanger or a brazed plate heat exchanger, to increase the subcooling of the first refrigerant stream once the refrigerant exits the accumulator and before entering the evaporator. However, the integration of the heat exchanger within the refrigeration system can be complex, and additional components result in higher costs and a larger volume of the refrigeration system.

It is therefore also desirable to increase the heat exchange between the two refrigerant streams without increasing the complexity of the refrigeration system and without causing a significant increase in the space required by the refrigeration system.

Disclosure of Invention

According to a first aspect, there is provided an accumulator heat exchanger for use within a refrigeration system, the accumulator heat exchanger comprising: an accumulator vessel having an interior volume for accumulating a refrigerant fluid, wherein the accumulator vessel has an axial extent and a radial extent; a first inlet conduit for gaseous refrigerant and a first outlet conduit for superheated gaseous refrigerant; a heat exchange coil disposed within the accumulator vessel so as to provide an axially extending outer gap between an inner surface of the accumulator vessel and a radially outer surface of the heat exchange coil, wherein the heat exchange coil surrounds an axially extending inner volume of the heat exchange coil; a second inlet conduit for subcooling the refrigerant fluid and a second outlet conduit for subcooling the refrigerant fluid, wherein the second inlet conduit and the second outlet conduit provide an inlet flow path and an outlet flow path for the heat exchange coil; and a baffle covering a cross section of the inner volume of the heat exchange coil without interrupting the outer gap, wherein: a first inlet conduit extends from the outside of the accumulator vessel into the accumulator vessel, passes through the baffle and terminates at an internal outlet within the internal volume of the heat exchange coil on the second side of the baffle, the first outlet conduit having an internal inlet disposed within the vessel outside of the internal volume of the heat exchange coil and on an opposite side of the baffle from the internal outlet of the first inlet conduit, wherein the first outlet conduit extends from the internal inlet through the baffle and through the internal volume of the heat exchange coil and to the outside of the accumulator vessel.

The accumulator vessel may be cylindrical, the axial extent and the radial extent of the accumulator vessel following the axial and radial dimensions of the cylinder, respectively.

The heat exchange coil may be a spiral coil having a cylindrical outermost surface and an axially extending inner volume having a circular cross-section. The heat exchange coil is positioned within the accumulator vessel to create an outer gap through which refrigerant within the accumulator vessel may pass. The outer gap thereby provides a flow path for refrigerant between the volume outside of the inner volume of the heat exchange coil at one end of the accumulator vessel and the volume outside of the inner volume of the heat exchange coil at the other end of the accumulator vessel. The outer gap extends from the inner periphery of the accumulator vessel to the radially outer periphery of the heat exchange coil. In examples where the accumulator vessel and heat exchange coil have cylindrical forms, the outer gap will have the form of an annular gap extending between the inner and outer circumferences of the accumulator vessel and heat exchange coil, respectively.

The baffles are provided to cover a cross section of the inner volume of the heat exchange coil adjacent the axial ends of the heat exchange coil. The baffles are provided such that, in use, a reduced volume of refrigerant flows from within the interior volume of the heat exchange coil to outside the interior volume of the heat exchange coil by passing through the axial ends of the heat exchange coil adjacent the baffles. Therefore, the length of the refrigerant flow path within the accumulator heat exchanger increases without increasing the volume of the accumulator vessel. In some examples, the baffle may seal the first end of the heat exchange coil such that, in use, refrigerant is prevented from passing from the interior volume of the heat exchange coil through the axial end of the heat exchange coil adjacent the baffle.

The diaphragm does not interrupt the outer gap between the inner surface of the accumulator vessel and the radially outer surface of the high pressure refrigerant coil, which means that there is a gap between the diaphragm and the accumulator vessel along substantially the entire circumference of the diaphragm. Thus, the diaphragm does not contact the inner surface of the accumulator vessel along substantially its entire circumference. In some examples, design constraints and other components may cause brief interruption of the outer gap.

In some examples, the separator is provided outside of the inner volume of the heat exchange coil and in contact with an axially outermost surface of an axially outermost winding (winding) of the heat exchange coil. Thus, the baffle separates the internal volume of the heat exchange coil from the volume of the accumulator outside of the internal volume of the heat exchange coil. The separator plate may extend beyond the radial extent of the windings of the heat exchange coil or may extend to the same radial extent as the windings of the heat exchange coil.

In other examples, the baffle is provided within the interior volume of the heat exchange coil and in contact with the radially inner surface of the heat exchange coil.

The first inlet conduit extends through the baffle with little or no gap between the first conduit and the baffle. The first inlet conduit terminates inside the accumulator vessel and is disposed at an outlet within the interior volume of the heat exchange coil. This configuration means that, in use, a reduced volume of refrigerant flows from the outlet of the first inlet conduit to the inlet of the first outlet conduit without passing through the outer gap, or that refrigerant is prevented from flowing from the outlet of the first inlet conduit to the inlet of the first outlet conduit without passing through the outer gap when the baffle seals the axial end of the heat exchange coil.

A length of the first outlet conduit extending within the interior volume of the heat exchange coil may be disposed adjacent the heat exchange coil.

Thus, the first outlet conduit is disposed in a radially outer region of the inner volume of the heat exchange coil, and therefore is closer to the windings of the heat exchange coil than the axis of the coil. The close proximity between the first outlet conduit and the heat exchange coil promotes a high heat exchange rate between the refrigerants respectively located therein.

The first outlet conduit may include a U-turn to extend axially through the interior volume of the heat exchange coil in opposite first and second directions.

Thus, the first outlet conduit changes direction within the accumulator vessel so as to extend the length of the conduit within the accumulator vessel, wherein a portion of the first outlet conduit extends in a first direction and another portion extends in a second direction generally parallel to the first direction. Thus, the first outlet conduit extends along an increased length adjacent the heat exchange coil. In use, heat exchange between the heat exchange coil and the refrigerant in the first outlet conduit is thereby increased. The first direction and the second direction are aligned with the axis of the heat exchange coil. A U-turn may be any combination of turns that cause the conduit to turn back on itself so as to initially flow in a first direction and then flow in an opposite second direction. Therefore, the length of the refrigerant flow path within the accumulator heat exchanger increases without increasing the volume of the accumulator vessel.

The U-turn may be disposed outside of the interior volume of the heat exchange coil.

Thus, the first outlet conduit extends through the baffle from outside the inner volume of the heat exchange coil, axially through the inner volume of the heat exchange coil in a first direction, to outside the inner volume of the heat exchange coil, axially through the inner volume of the heat exchange coil in a second direction. When there is only one U-turn, the first outlet conduit then extends through the baffle and to the outside of the accumulator vessel. Thus, by extending through the entire length of the coil, the length of the path for heat exchange between the subcooled refrigerant in the heat exchange coil and the superheated refrigerant in the outlet conduit increases.

The first outlet conduit including the U-turn may also include an oil port to supply refrigerant oil to the gaseous refrigerant flow within the first outlet conduit. By mixing the gaseous refrigerant with the refrigerant oil within the accumulator, a mixture of gaseous refrigerant and refrigerant oil may be provided to the compressor. This ensures that the compressor is lubricated via the refrigerant oil while preventing liquid refrigerant from entering the compressor. The oil port is capable of metering the addition of refrigerant oil to the gaseous refrigerant to ensure that a proper mixture is obtained to properly lubricate the compressor. The U-turn in the first outlet conduit allows the first outlet conduit and the oil port to be located within the accumulation zone of refrigerant oil. Thus, the U-turn of the first outlet conduit is provided such that during the intended use of the accumulator, the U-turn is disposed towards the base of the accumulator vessel.

The first inlet conduit and the first outlet conduit may enter and leave the accumulator vessel through a first cover of the accumulator vessel, respectively.

The first cap may be disposed at an axial end of the accumulator vessel. The cap advantageously maintains a seal where the conduit passes through the cap.

The second inlet conduit and the second outlet conduit may also enter and leave the accumulator vessel through the first cover of the accumulator vessel, respectively. Alternatively, the second inlet conduit and the second outlet conduit may enter and leave the accumulator vessel through second caps of the accumulator vessel disposed at opposite axial ends of the accumulator vessel, respectively. If the second outlet conduit exits the accumulator vessel at the same axial cap as the second inlet conduit enters the accumulator vessel, either the second inlet conduit or the second outlet conduit extends through the inner volume of the heat exchange coil to the respective cap.

In an alternative example, where the first outlet conduit does not include a U-turn or includes an even number of U-turns, the first inlet conduit enters the accumulator vessel through the first cap and the first outlet conduit exits the accumulator vessel through the second cap of the accumulator vessel at an opposite axial end of the accumulator vessel. Similarly, some examples include a second inlet conduit and a second outlet conduit that enter and exit the accumulator vessel through caps at opposite axial ends of the accumulator vessel, respectively.

The pitch of the heat exchange coils may be such that adjacent windings are in contact.

The heat exchange coil may be, for example, a circular helical coil. The pitch of the heat exchange coils may be constant or may vary along the axial length of the coils. In the event of contact between adjacent windings of the heat exchange coil, there is no path for any meaningful refrigerant flow within the accumulator vessel through the axially extending and circumferentially extending surfaces of the coil. Thus, by providing a coil having a contact area between adjacent windings, the volume of refrigerant passing from within the inner volume of the coil to the outer gap is reduced in use without first exiting the inner volume of the heat exchange coil. In some embodiments, adjacent windings are in sufficient, continuous contact such that there is no path for the refrigerant to pass from within the inner volume of the coil to the outer gap without first exiting the inner volume of the heat exchange coil. In some embodiments, adjacent windings are sealed together so as to completely prevent flow between adjacent windings. Alternatively, adjacent windings may be contacted without an added sealing mechanism, such that a small leak may occur but no meaningful volume flows between the windings. Another possibility is coil winding spacing, where a barrier is added between the windings to limit and/or prevent refrigerant flow between the inner volume and the outer gap. Thus, the primary flow path for at least a majority of the refrigerant extends through the inner volume of the heat exchange coil and exits the inner volume at an axial end opposite the axial end having the baffles. The flow path for the refrigerant then extends along the outer gap towards the first outlet conduit inlet. The length of the flow path for the refrigerant within the accumulator vessel is thus increased such that in use the heat exchange between the refrigerant in the accumulator vessel and the sub-cooled refrigerant in the heat exchange coil is also increased.

The baffles may be brazed to the heat exchange coil.

The baffles are thus bonded to the heat exchange coils. The baffles may be brazed to the heat exchange coil along the circumference of the baffles or only at certain points along the circumference of the baffles. In the case of brazing the separator plate along the entire circumference, a seal is thus provided between the separator plate and the heat exchange coil, such that there is no path for the refrigerant to pass between the separator plate and the heat exchange coil.

The second inlet conduit may be connected to the heat exchange coil at an axial end of the coil adjacent the baffle. In use, subcooled refrigerant flows through the coil toward the axial end of the coil opposite the axial end adjacent the separator plate.

Alternatively, the second inlet conduit may be connected to the heat exchange coil at an axial end of the coil opposite the axial end adjacent the baffle. In use, subcooled refrigerant flows through the coil toward the axial ends adjacent the separator plates.

According to another aspect, there is provided a refrigeration system comprising: an accumulator heat exchanger, a compressor, an evaporator, an expansion valve and a condenser as in the first aspect and optionally including other features discussed above, wherein the first inlet conduit and the first outlet conduit are positioned between the evaporator and the compressor such that the first refrigerant flow path sequentially extends from the evaporator to the first inlet conduit to the first outlet conduit to the compressor, and the second inlet conduit and the second outlet conduit are positioned between the condenser and the expansion valve such that the second refrigerant flow path sequentially extends from the condenser to the second inlet conduit to the second outlet conduit and to the expansion valve.

In some embodiments, the first refrigerant flow path may extend directly from the evaporator to the first inlet conduit and/or directly from the first outlet conduit to the compressor, i.e., not through another component therebetween, other than a connected refrigerant line or tube. In other embodiments, the first refrigerant flow path may extend through additional components between the evaporator and the first inlet conduit, and/or additional components between the first outlet conduit and the compressor, but will maintain the order enumerated above with respect to the evaporator, the first inlet conduit, the first outlet conduit, and the compressor.

In some embodiments, the second refrigerant flow path may extend directly from the condenser to the second inlet conduit and/or directly from the second outlet conduit to the expansion valve, i.e., not through another component therebetween, other than the connected refrigerant line or tube. In other embodiments, the second refrigerant flow path may extend through additional components between the condenser and the second inlet conduit, and/or additional components between the second outlet conduit and the expansion valve, but will maintain the order enumerated above with respect to the condenser, the second inlet conduit, the second outlet conduit, and the expansion valve.

The first inlet conduit may be directly connected to the evaporator.

Thus, a flow path is provided between the evaporator and the first inlet conduit, and this flow path does not extend through any additional components between the evaporator and the first inlet conduit other than the connected refrigerant lines or tubes.

The first outlet conduit may be directly connected to the compressor.

Thus, a flow path is provided between the first outlet conduit and the compressor, and this flow path does not extend through any additional components between the first outlet conduit and the compressor, except for the connected refrigerant lines or tubes.

The refrigeration system may be suitable for use in transportation applications. For example, the refrigeration system may be suitable for use in a refrigerated vehicle and/or a trailer. Such refrigerated vehicles and trailers are commonly used to transport perishable goods in cold chain distribution systems. The refrigeration system may be mounted to a vehicle or trailer in operative association with a cargo space within the vehicle or trailer for maintaining a controlled temperature environment within the cargo space.

The refrigeration system may be suitable for use in HVAC systems or air conditioning systems that may be installed in buildings, vehicles, and the like.

According to another aspect, there is provided a method of heat exchange using an accumulator heat exchanger as described above, the method comprising simultaneously supplying gaseous refrigerant to a first inlet conduit and subcooled liquid refrigerant to a second inlet conduit.

The first inlet conduit thereby introduces gaseous refrigerant into the interior volume of the accumulator vessel. A second inlet conduit directs subcooled refrigerant into a heat exchange coil within the accumulator vessel.

A mixture of gaseous refrigerant and liquid refrigerant may enter the accumulator vessel through the first inlet conduit. Liquid refrigerant may accumulate in a pool within the accumulator vessel and may periodically evaporate from the accumulator vessel. Gaseous refrigerant may accumulate throughout the vessel and may generally flow from the outlet of the first inlet conduit to the inlet of the first outlet conduit.

The general flow path of refrigerant exiting the first inlet conduit will be through the interior volume of the heat exchange coil and exit the interior volume at the axial end of the coil opposite the axial end adjacent the baffle, reverse direction, and flow through the outer gap along the length of the accumulator vessel and into the interior inlet of the first inlet conduit disposed on the opposite side of the baffle from the outlet of the first inlet conduit.

Due to the heat exchange with the subcooled refrigerant in the heat exchange coil, the gaseous refrigerant will become superheated gaseous refrigerant as it travels through the accumulator vessel. The superheated refrigerant is at a temperature above the vapor point of the refrigerant. The supercooled refrigerant is at a temperature lower than the bubble (liquid) point of the refrigerant.

The gaseous refrigerant in the first inlet conduit, the accumulator vessel and the first outlet conduit is at a lower pressure than the refrigerant in the second inlet conduit, the heat exchange coil and the second outlet conduit. As a result, the vapor point of the refrigerant in the first inlet conduit, accumulator vessel, and first outlet conduit will be lower than the vapor point of the refrigerant in the second inlet conduit, heat exchange coil, and second outlet conduit. Thus, the gaseous refrigerant may be at a lower temperature than the subcooled liquid refrigerant. Accordingly, heat exchange occurs via heat transfer from the subcooled liquid refrigerant to the superheated refrigerant. Thus, the accumulator heat exchanger serves to further cool the subcooled refrigerant and to further heat the gaseous refrigerant to form superheated gaseous refrigerant. As a result, evaporation of the refrigerant supplied via the first inlet conduit is promoted, and the volume of the liquid refrigerant accumulation zone in the accumulator is reduced. The subcooled refrigerant exiting the accumulator heat exchanger also has a greater cooling capacity due to its reduced temperature.

The accumulator heat exchanger may be part of a refrigeration system, wherein the refrigeration system includes: a compressor, an evaporator, an expansion valve, and a condenser, and the heat exchanging method includes: the method includes supplying refrigerant from an evaporator to a first inlet conduit, supplying superheated gaseous refrigerant from a first outlet conduit to a compressor, supplying subcooled liquid refrigerant from a condenser to a second inlet conduit, and supplying subcooled liquid refrigerant from the second outlet conduit to an expansion valve.

In some embodiments, the refrigerant may be supplied directly from the evaporator to the first inlet conduit, and/or the superheated gaseous refrigerant may be supplied directly from the first outlet conduit to the compressor, i.e., without passing through another component therebetween. In other embodiments, the refrigerant may flow through additional components between the evaporator and the first inlet conduit, and/or additional components between the first outlet conduit and the compressor, but the order listed above with respect to the evaporator, the first inlet conduit, the first outlet conduit, and the compressor will be maintained.

In some embodiments, the subcooled refrigerant may be supplied directly from the condenser to the second inlet conduit, and/or may be supplied directly from the second outlet conduit to the expansion valve, i.e., without passing through another component therebetween. In other embodiments, the subcooled refrigerant may flow through additional components between the condenser and the second inlet conduit, and/or additional components between the second outlet conduit and the expansion valve, but the order listed above with respect to the condenser, the second inlet conduit, the second outlet conduit, and the expansion valve will be maintained.

Gaseous refrigerant may be supplied directly from the evaporator to the first inlet conduit.

The gaseous refrigerant is thereby supplied from the evaporator to the accumulator vessel without the gaseous refrigerant entering the additional member between the evaporator and the first inlet conduit. A combination of gaseous refrigerant and liquid refrigerant may be provided from the evaporator to the accumulator vessel through the first inlet conduit.

The superheated gaseous refrigerant may be supplied directly from the first outlet conduit to the compressor.

Thus, superheated gaseous refrigerant is provided from the accumulator vessel to the compressor without passing through additional components of the refrigeration system between the first outlet conduit and the compressor. Any liquid refrigerant introduced into the accumulator vessel will pool within the vessel and not flow through the first outlet conduit to the compressor.

Drawings

Certain embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

fig. 1 shows an external perspective view of an accumulator heat exchanger.

Fig. 2 shows a perspective view of a section of the accumulator heat exchanger in another plane parallel to the axis of the accumulator heat exchanger.

Fig. 3 shows a section of the accumulator heat exchanger in a plane parallel to the axis of the accumulator heat exchanger.

Fig. 4 shows a perspective view of a section of an accumulator heat exchanger.

Fig. 5 shows a perspective view of a section of the accumulator heat exchanger in a plane perpendicular to the axis of the accumulator heat exchanger.

Fig. 6 shows a perspective view of a section of the accumulator heat exchanger in another plane perpendicular to the axis of the accumulator heat exchanger.

Fig. 7 shows a schematic of a refrigeration system.

Detailed Description

As seen in fig. 1, the accumulator heat exchanger 100 includes an accumulator vessel 102 having an interior volume 108 (see fig. 2) for accumulating refrigerant. The accumulator vessel 102 of fig. 1 is generally cylindrical with an axial extent and a radial extent. A cap 104 at the axial end of the accumulator vessel provides a slightly domed end to the accumulator vessel 102. The first inlet conduit 110 and the second inlet conduit 120 extend from the outside of the accumulator vessel 102 to the inside of the accumulator vessel 102. The first outlet conduit 112 and the second outlet conduit 122 extend from the inside of the accumulator vessel 102 to the outside of the accumulator vessel 102. The first and second inlet conduits 110, 120 and the first and second outlet conduits 112, 122 extend through the same axial end of the accumulator vessel 102. The seal 106 is provided where the first and second inlet conduits 110, 120 and the first and second outlet conduits 112, 122 pass through the cover 104.

As seen in fig. 2, a heat exchange coil 124 is provided within the accumulator vessel 102. The heat exchange coil 124 is in the form of a spiral coil such that its outer surface defines a cylinder. Thus, the heat exchange coil 124 encloses an axially extending inner volume 126. The heat exchange coil 124 is disposed within the accumulator vessel 102 to provide an axially extending outer gap 130 between the inner surface 106 of the accumulator vessel 102 and a radially outer surface 128 of the heat exchange coil 124. Due to the cylindrical form of the accumulator vessel 102 and the heat exchange coil 124, the outer gap 130 is annular in shape. The second inlet conduit 120 and the second outlet conduit 122 are connected to the heat exchange coil 124 such that the second inlet conduit 120 and the second outlet conduit 122 provide an inlet flow path and an outlet flow path for the heat exchange coil 124. In use, subcooled refrigerant flows from second inlet conduit 120 through heat exchange coil 124 and to second outlet conduit 122. A second inlet conduit 120 and a second outlet conduit 122 enter and leave the accumulator vessel 102 through the same end, respectively.

A baffle 132 is disposed within the accumulator vessel 102 to cover the cross section of the heat exchange coil 124. The baffle 132 is disposed outside of the interior volume of the heat exchange coil 124 and is in contact with the axial ends of the heat exchange coil 124. The second inlet conduit 120 extends through the interior volume 126 of the heat exchange coil 124 to provide an inlet flow path for the heat exchange coil 124 such that, in use, refrigerant flows through the heat exchange coil from an axial end furthest from the baffle toward an axial end adjacent the baffle.

The first inlet conduit 110 extends from the outside of the accumulator vessel 102, through the cover 104 of the accumulator vessel 102, through the baffle 132, and to the outlet 114 (see fig. 3) disposed within the interior volume 126 of the heat exchange coil 124. Thus, in use, refrigerant is delivered by the first inlet conduit 110 to the interior volume 126 of the heat exchange coil 124. Liquid refrigerant will pool within accumulator vessel 102, while gaseous refrigerant will flow to first outlet conduit 112 for removal from accumulator vessel 102.

As shown in fig. 3, the first outlet conduit 112 has an inlet 116, the inlet 116 being disposed outside of the interior volume 126 of the heat exchange coil 124 and on the opposite side of the baffle 132 from the outlet of the first inlet conduit 114. The configuration of the baffle 132, the outlet of the first inlet conduit 114 and the inlet of the first outlet conduit 116 on opposite sides of the baffle 132, and the annular gap 130 create a flow path for refrigerant that travels through the accumulator vessel 102 at least twice substantially along the length of the accumulator vessel.

In use, the refrigerant within the heat exchange coil 124 is at a higher temperature than the refrigerant within the first inlet conduit 110, the interior volume 108 of the accumulator vessel, and the first outlet conduit 112. Thus, heat will transfer from the refrigerant within the heat exchange coil 124 to the refrigerant within the first inlet conduit 110, the interior volume 108 of the accumulator vessel, and the first outlet conduit 112. Thus, the refrigerant exiting accumulator vessel 102 via first outlet conduit 112 will be at a higher temperature than the refrigerant entering accumulator vessel 102 via first inlet conduit 110. Thus, the refrigerant exiting accumulator vessel 102 via second outlet conduit 122 will be at a lower temperature than the refrigerant entering accumulator vessel 102 via second inlet conduit 120.

A first outlet conduit 112 extends from the inlet 116, through the partition 132 and through the interior volume 126 of the heat exchange coil 124. In the example shown in fig. 3 and 4, once outside the interior volume 126 of the heat exchange coil 124, the first outlet conduit 112 includes a U-turn 118 before extending back through the interior volume 126 of the heat exchange coil 124. The first outlet conduit 112 is positioned adjacent the heat exchange coil 124 when within the interior volume 126 of the heat exchange coil 124 such that, in use, heat exchange is facilitated between the first outlet conduit and the refrigerant within the heat exchange coil. This is shown more clearly in fig. 5 and 6, where the first outlet conduit before and after the U-turn 118 is shown as being proximate to the heat exchange coil 124. The axis of the first inlet conduit 112 extending through each length of the interior volume 126 of the heat exchange coil 124 is positioned closer to the windings of the coil 124 than to the central axis of the coil 124.

In other examples, the first outlet conduit 112 does not include a U-turn, and the first outlet conduit 112 may instead extend in only one direction within the interior volume 126 of the heat exchange coil 124. In this case, the first outlet conduit 112 exits the accumulator vessel 102 at an axial end opposite the end of the accumulator vessel 102 that includes the baffle 132.

Fig. 4 shows an example in which the first outlet conduit 112 includes a U-turn 118 and an oil port 134. When used in the orientation shown in the figures, refrigerant oil will collect within accumulator vessel 102 at the axial end where U-turn 118 is located. When the level of accumulated oil reaches the oil port 134, refrigerant oil will enter the first inlet conduit 112 through the oil port 134. In particular, the action of the refrigerant gas flowing through the first inlet conduit will cause the oil to become entrained within the flow in the first outlet conduit 112. In this way, the refrigerant oil may be metered such that the supply of refrigerant oil to the compressor may be controlled. Using an accumulator heat exchanger with this oil port allows refrigerant oil to be provided to the compressor without also providing liquid refrigerant to the compressor.

Fig. 5 shows an example in which a baffle 132 is disposed within the interior volume of the heat exchange coil 124 and in contact with the radially inner surface of the heat exchange coil 124. The first inlet conduit 110 and the second inlet conduit 120 extend through the partition 132.

Fig. 6 shows a section of the accumulator vessel 102 perpendicular to the axis of the accumulator vessel 102 and at a point where the first inlet conduit 110 does not extend. At this cross-section, only the first outlet conduit 112 and the second inlet conduit 120 are disposed within the interior volume 126 of the heat exchange coil 124.

Fig. 7 shows a schematic diagram of a refrigeration system 200 including the accumulator heat exchanger 100 described above. The refrigeration system 200 includes a compressor 210, a condenser 220, an expansion valve 230, and an evaporator 240. The condenser 220 is connected to the second inlet conduit 120 of the accumulator 100. An expansion valve 230 is connected to the second outlet conduit 112 of the accumulator 100.

Refrigerant flows sequentially from the compressor 210 to the condenser 220, to the heat exchange coil 124 within the accumulator heat exchanger 100, to the expansion valve 230, to the evaporator 240, to the first inlet conduit 110 and the first outlet conduit 112 of the accumulator heat exchanger 100, and back to the compressor 210.

The refrigerant exiting the condenser will be at a relatively high pressure (compared to the refrigerant exiting the evaporator 240) and will be a liquid. Condenser 220 causes heat rejection from the refrigerant to the surrounding environment by cooling the refrigerant to its saturation temperature (at which point the gaseous refrigerant condenses to a liquid). Latent heat generated during condensation is transferred to the surrounding environment. Condenser 220 may have sufficient cooling capacity to reduce the temperature of the liquid below the saturation temperature to produce a subcooled refrigerant. The high pressure within the condenser 220 means that the saturation temperature of the refrigerant is higher than the saturation temperature of the refrigerant in the evaporator 240 at a lower pressure. Accordingly, the refrigerant temperature of the supercooled liquid refrigerant may be higher than the temperature of the gaseous refrigerant supplied by the evaporator 240. Accordingly, heat is transferred from the subcooled refrigerant in heat exchange coil 124 to the gaseous refrigerant in first inlet conduit 110, accumulator internal volume 108, and first outlet conduit 112.

The increased degree of subcooling of the refrigerant exiting the second outlet conduit 122 in turn increases the cooling capacity of the refrigerant such that once it is supplied to the evaporator 240, an increased amount of heat is carried away from the surrounding environment as the liquid evaporates into a gas. As a result, the efficiency of the refrigeration system is improved.

Providing heat to the refrigerant supplied to the accumulator vessel 102 via the first inlet conduit 110 will reduce the proportion of the refrigerant in the liquid phase. As a result, less liquid refrigerant accumulates in the accumulator and a greater amount of gaseous refrigerant is available to continue through the refrigeration system.

The use of the accumulator heat exchanger described above within the refrigeration system allows these benefits to be achieved while avoiding increasing the complexity of the refrigeration system and increasing the space required by the refrigeration system. Thus, the refrigeration system and its use are suitable for applications such as transport refrigeration in which the refrigeration system may be mounted to a vehicle or trailer in operative association with a cargo space within the vehicle or trailer for maintaining a controlled temperature environment within the cargo space.

Claims

1. An accumulator heat exchanger for use within a refrigeration system, the accumulator heat exchanger comprising:

an accumulator vessel having an interior volume for accumulating a refrigerant fluid, wherein the accumulator vessel has an axial extent and a radial extent;

a first inlet conduit for gaseous refrigerant and a first outlet conduit for superheated gaseous refrigerant;

a heat exchange coil disposed within the accumulator vessel so as to provide an axially extending outer gap between an inner surface of the accumulator vessel and a radially outer surface of the heat exchange coil, wherein the heat exchange coil surrounds an axially extending inner volume of the heat exchange coil;

a second inlet conduit for subcooled refrigerant fluid and a second outlet conduit for subcooled refrigerant fluid, wherein the second inlet conduit and the second outlet conduit provide an inlet flow path and an outlet flow path for the heat exchange coil; and

a baffle covering a cross section of the inner volume of the heat exchange coil without interrupting the outer gap, wherein:

the first inlet conduit extending from outside the accumulator vessel into the accumulator vessel, through the baffle and terminating at an internal outlet within the internal volume of the heat exchange coil on a second side of the baffle,

the first outlet conduit has an internal inlet disposed within the vessel outside of the internal volume of the heat exchange coil and on an opposite side of the baffle from the internal outlet of the first inlet conduit, wherein the first outlet conduit extends from the internal inlet through the baffle and through the internal volume of the heat exchange coil and to the outside of the accumulator vessel.

2. The accumulator heat exchanger of claim 1 wherein a length of the first outlet conduit extending within the interior volume of the heat exchange coil is disposed adjacent the heat exchange coil.

3. The accumulator heat exchanger of claim 1 or claim 2, wherein the first outlet conduit includes a U-turn so as to extend axially in opposite first and second directions through the inner volume of the heat exchange coil.

4. The accumulator heat exchanger of claim 3 wherein the U-turn is disposed outside of an interior volume of the heat exchange coil.

5. The accumulator heat exchanger of claim 3 or claim 4, wherein the first outlet conduit includes an oil port for providing refrigerant oil from within the accumulator vessel into the first outlet conduit.

6. The accumulator heat exchanger of claim 3, claim 4, or claim 5, wherein the first inlet conduit and the first outlet conduit enter and leave the accumulator vessel through a first cover of the accumulator vessel, respectively.

7. An accumulator heat exchanger according to any preceding claim wherein the pitch of the heat exchange coils is such that adjacent windings are in contact.

8. The accumulator heat exchanger according to any preceding claim wherein the separator plates are brazed to the heat exchange coil.

9. A refrigeration system, comprising:

the accumulator heat exchanger of any preceding claim,

the air flow of the compressor is controlled by the air flow,

the evaporator is provided with a plurality of air inlets,

expansion valve, and

a condenser, wherein

The first inlet conduit and the first outlet conduit are positioned between the evaporator and the compressor such that a first refrigerant flow path extends sequentially from the evaporator to the first inlet conduit, to the first outlet conduit to the compressor, and

the second inlet conduit and the second outlet conduit are positioned between the condenser and the expansion valve such that a second refrigerant flow path extends sequentially from the condenser to the second inlet conduit, to the second outlet conduit, and to the expansion valve.

10. The refrigeration system of claim 9, wherein the first inlet conduit is directly connected to the evaporator.

11. The refrigeration system of claim 9 or claim 10, wherein the first outlet conduit is directly connected to the compressor.

12. A method of heat exchanging using the accumulator heat exchanger of any one of claim 1 to claim 8, the method comprising,

simultaneously supplying gaseous refrigerant to the first inlet conduit and subcooled liquid refrigerant to the second inlet conduit.

13. The method of heat exchange of claim 12, wherein the accumulator heat exchanger is part of a refrigeration system, wherein the refrigeration system comprises:

the air flow of the compressor is controlled by the air flow,

the evaporator is provided with a plurality of air inlets,

expansion valve, and

a condenser, and the method of heat exchange comprises:

refrigerant is supplied from the evaporator to the first inlet conduit,

a superheated gaseous refrigerant is supplied from the first outlet conduit to the compressor,

supplying subcooled liquid refrigerant from said condenser to said second inlet conduit, and

a subcooled liquid refrigerant is supplied from the second outlet conduit to the expansion valve.

14. The method of heat exchange of claim 13, wherein gaseous refrigerant is supplied directly from the evaporator to the first inlet conduit.

15. A method of heat exchange according to claim 13 or claim 14 wherein superheated gaseous refrigerant is supplied directly from the first outlet conduit to the compressor.